#include<iostream>
using namespace std;
#include <stdio.h>
#include <stdlib.h>
#include <string>
int main()
{
  string str = "Hello World!";
  cout<<str<<endl;
  printf("%s\n",str.c_str());
  char* name = getenv("USER");
  string user(name);
  cout<<user.c_str()<<endl;
  printf("%s\n",getenv("USER"));
  return 0;
}
